Cooler for viscous liquids



Sept. 6, 1949. s. K. ANDERsr-:N Re. 23,144

COOLER FOR VISCOUS LIQUIDS Original Filed March l0, 1945 5 Sheets-Sheetl 2@ l x f 1 25 1o 25 44 5@ 46 74 12 50. 26 Snnentor: 5mn-w /ffyofRsE/y.

Gtorneg.

SePt- 6 1949 s. K. ANDERSEN COOLER FOR VISCOUS LIQUIDS 5 Sheets-Sheet 2Original Filed March 10, 1945 3 :mentor g Sept 6, 1949. s. K. ANDERSENRe. 23,144

COOLER FR VISCOUS LIQUIDS Original Filed March 10, 1945 5 Sheets-Sheet 3rmentor:

Gttorneg.

Sept- 6, 1949- s. K. ANDERSEN COLER FOR VISCOUS LIQUIDS 5 Sheets-Sheet 4Original Filed March l0. 1945 Snventor:

G tforneg Sept 6, 1949. s. K, ANDERSEN Re. 23,144

COOLER FOR VISCOUS LIQUIDS Original Filed March lO, 1945 5 SheetS-Sheet5 |250 wi si MIHWW? 22/ E", w

IO -f 47 4? 7| 65 70 l IN L EN TOR. SOREN K. ANDERSEN K auf 'l ReiuuedSept. 6, 1949 COOLER FOR VISCOUS LIQUIDE Soren K. Andersen,

to The Garrett Corp Los Angeles, Calif., assigner eration, AiresearchMannfacturing Company division,

Los Angeles,

Calif., a corporation of California Original No. 2,449,922, datedSeptember 21, 1948,

Serial No. 582,080, Mar for reissue March 24,

l Claims.

This invention relates to coolers for liquids which are viscous whencold, and is particularly useful in oil coolers for aircraft engines.

Such oil coolers have as their primary function to regulate thetemperature, and thus the viscosity, of the lubricating oil of anaircraft engine, and are required to perform this function under widelyvarying conditions of operation. At times they are burdened with a heavycooling load, for example-when the temperature of the ambient air ishigh, and for this purpose the cooler must have a high heat exchangecapacity. Consequently, it is customary to provide the cooler with alarge number of tubes for the flow of a coolant, which tubes are spacedrelatively closely together to provide restricted passages for the mostecient exchange `of heat between the oil flowing through such passagesand the coolant flowing through the tubes.

At other times the coolers may be required to operate in ambient airhaving a temperature far below zero, and in many cases the descent tosuch subzero temperatures may be quite abrupt, and under such conditionsthe mechanism which is usually provided for regulating the quantity ofcoolant flowing through the tubes, may not act quickly enough to preventa rapid chilling of the tubes sufficient to cause the layers of oiladjacent the outer surfaces of the tubes to congeal thereagainst or tobecome so viscous as to adhere substantially immovably to such tubesurfaces. In other cases, the aircraft may be forced to stand in subzeroweather for sucient length of time to permit the oil within the coolercore to thicken. Under such conditions, the resistance of the relativelyrestricted passages between the heat exchange tubes to the flow of thethickened oil therethrough, may become so great as to virtually preventany substantial flow through said pas# ages, even under the highpressures developed by the pumping apparatus of the oil circulatingsystem. The restriction of the passages between the tubes by thecongealment of layers of oil against the outer surfaces of the tubes,heightens this increased core resistance.

It is customary to employ, in such coolers, a warm up chamber in thenature of a bypass between the inlet and outlet of the cooler, which maybe subjected, through suitable yielding valve means, to sufficientresistance to the flow of the oil therethrough to normally urge the flowthrough the cooler core, but operative to bypass the oil or asubstantial portion thereof when the core resistance becomes abnormallyhigh as aforesaid. The oil thus bypassed is not subjected to ch 1l),1945. Application 1949, Serial No. 83,231 (Cl. 257-128) any substantialcooling effect and consequently may acquire and maintain a sulcientlyhigh temperature to impart heat to the cooler for the purpose of thawingor reducing the viscosity oi the thickened oil therein. The use of suchwarm up bypassing means has been quite common for a number of years, buteven though supplied with such warming up means, coolers have oftenfailed under severe operation conditions. In many cases, such coolerswould, under severe low tem'- perature operating conditions, display aprogressive waxing of the tubes beginning in the center oi' the coolerand spreading outwardly, accompanied by a progressive localization ofincreasing high temperature oil at the periphery of the core adjacentthe shell. It now appears that this was due to a haphazard arrangementof tube spacing, with restriction or stoppage of the flow in some areasand excess spacing in other areas, producing what may be termedchanneling of the ilow in overlarge spaces of inadequate iiowresistance, resulting in an undesirably excessive bypassing of the ilowin localized areas, and inadequate distribution into the core. Suchbypassing aggravated the waxing in the more remote areas of the core.

Having in mind the foregoing problems, the general object of the presentinvention is to provide a cooler for liquids that are viscous when coldwhich is adapted to provide a maximum of forced distribution of theliquid into the core' under congealment conditions wherein the layers ofliquid adjacent the tube surfaces become so viscous as to adheresubstantially immovably to the tube surfaces or to form waxed nlmthereon.

More specifically, it is an object of the invention to provide an oilcooler having coolant tubes which are spaced sufiiciently closely toprovide adequate cooling eiliciencyunder heavy cooling loads, and yetwhich is adapted to maintain a path or paths of "free ow through thecooler core from the inlet to the outlet in which the liquid ispermitted not only to ilow adjacent the jacketed walls which are warmedby the circulation oi a heated fluid through a warm up chamber, but arealso permitted and urged under pressure to penetrate the core so as topromote antlcongealing and de-congealing ilow into the heart of the corewhere the waxing has been previously most pronounced.

It is a further object to provide a cooler of the 'character described,having well dened iiow passages between heated inner areas of the shellwalls and tubes adjacent thereto, communicating with flow passagespenetrating into the cooler core (preferably along the bailes whichdivide the core into ilow chambers), all of said now passages being oiless now resistance than the passages between the majority of the tubesand being un restricted throughout their length and so connected to eachother as. to collectively define a "free flow" channel which not onlyextends substantially uninterruptedly from the inlet to the outlet ofthe cooler, but also penetrates into the core and is adapted to directand urge the iiow of warmed oil into the core.

A further object of the invention is to provide a cooler of thecharacter set forth herein having one or more bailies with portsadjacent the ends thereof. and with supplementary ports spaced from thefirst named ports toward the center of the cooler and adapted to providefor a limited bleeding of liquid from one tlow chamber to another, suchas to facilitate the free now" circulation under congeaixnentconditions.

A further object of the invention is to provide a cooler having a corewhich is composed of a purality or bundles of tubes separated bybattles, a portion oi the tubes at the periphery of the core being o!flattened cross section, such as to better round out the peripheralcontour of the core, and in which at least some of the ilattened tubesare provided, near their ends with portions of reduced thicknessdefining between them ports or apertures for establishing bettercommunication between the header free ow passages adjacent the innersurface of the shell and the passage between the tubes.

The present invention is a continuation-impart of my prior copendingapplications now abandoned, Serial No. 456,033, for Oil cooler havingquick thaw-out means, iiled August 25, 1942, and Serial No. 410,156, forOil cooler, iiled December 26, 1942.

Further objects and advantages of the invention will be brought out inthe following parts of the specification.

Referring to the drawings which are for illustrative purposes only,

Fig. 1 is a sectional view of the cooler taken on the verticallongitudinal median plane of the cooler;

Fig. 2 is a cross sectional view taken as indicated by the line 2--2 oi'Fig. 1:

Fig. 3 is a perspective view looking toward the bottom of the inlet andoutlet fitting of the cooler;

Fig. 4 is a perspective view, to reduced scale, of the cooler muif;

Fig. 5 is a perspective view o! one of the baille plates of the cooler;

Fig. 6 is a perspective view oi' a pinched halftube employed in theVcooler:

Fig. '1 is an enlarged fragmentary section taken as indicated by theline 1-1 of Fig. 6;

Fig. 8 is a view oi one side of a cooler embodying the invention withportions of the warm up jacket and shell wall broken away to illustratea core periphery composed o! tubes of normal proportioning the shelldimensions; and

Fig. 9 is a detailed sectional view of the same taken as indicated bythe line 3-3 of Fig. 8.

As best shown in Figs. i and 2, the oil cooler comprises a drum or shellIII of tubular form, that is to say, this shell is open at both ends soas to have the characteristics of a tube. The shell I3 is preferablycylindric, and around the exterior there is a muil Il dening a warrn upchamber i2. The interior of the shell is divided into a series of iiowchambers I3 by baille plates |4 which are of rectangular outline. andextend from side to side oi the shell Il, and have a length nearly algreat as that of the shell I3.

Referring to Fig, 5, each balie plate I4 has near one end port meansconsisting of aligned openings i3 and I3. The openings It are close tothe side edges, and preferably are open to the side edges l1, for apurpose which will be here inafter described, Between the ports il andI3 and the center of the plate there are supplementary openings i8. Thebaille plate |4 is of wave form, at least the ends I3 and 2e thereof. tocooperate with hexagonal tube ends, as shown in Fig. 2. Along the sideof the baille plate, between the ends I3 and 20, there are flanges 2|for engagement with the inner face of the shell lll, also as shown inFig. 2.

The mui! Il, as shown in Fig. 4, comprises a wall 22 curved to nearcylindric form so that there will be a space 23 between the ends 24 o!the wall 22. Flanges 25 are bent inward from the curved edges oi thewall 22, the inner edges 23 of these ilanges 25 engaging the externalface of the shell Ill, and being joined therewith, as by soldering, soas to form the end closures for the warm-up chamber I2 oi the cooler.

The mui! is mounted on the shell lli so that the gap 23 between the ends24 thereof will be disposed at the top of the cooler, and in thin spacethere is a litting 21 having the general form of an inverted rectangularpan. This ntting, as shown in Fig. 3, has a top wall 23, end walls 29,and side walls 3|) and 3|, defining within the tting 21 a space which isdivided by transverse walls 32 and 32' into an inlet chamber 33, bypasschamber 34, and outlet chamber 35, with cooperating inlet port 3B,bypass port 31, and outlet port 33, all oi' which are preferably formedin the top wall 23 of the fitting 21. Along each side wall and 3| oi thefitting 21, there is an outstanding lip 33, the upper portion of whichlip extends parallel to the upper face of the shell Il, and the endportions 4| of the lip curve downward to meet the face of the shell I0.These lips 39 project under the ends 24 of the wall 22 from which themuil' is formed. and the end portions 4I of the lips lie within the endsof the anges 25 of the drum and muff The ends 24 of the mun' and the lip39 of the fitting, lying thus in overlapping relation, are solderedtogether so that strong joints are made therebetween. The lower faces ofthe walls 23, 30, 3|, 32, and 32', which engage the upper surface of theshell i0, are soldered to the shell so that the fitting 21 is rigidlysecured in place.

Referring again to Fig. 3, it will be noted that the forward interiorportion of the side wall 3| is cut away, below the lip 33, to provide aport 42 for connecting the inlety chamber 33 of the fitting 31 with oneend of the warm up chamber I2. This port 42 extends from the partitionwall 32 to a point proximate to the end wall 23 of the inlet chamber 33.The side wall 30 of the fitting 21 is cut away between the partitionwalls 32 and 32', and below the lip 33 which projects outward from theside wall 33, to provide a port 43 which connects the other end of thewarm up chamber I2 with the bypass chamber 34 of the nttlng 21.

As shown in Fig. 1, the baille plates |4 are alternated with respect tothe ports thereof so that the ports Il and I3 of consecutive bailleplates will be disposed at opposite ends of the cooler. These ports IIand I8 and likewise the supplementary ports i8 connect the sections i3in series so that a zig-sag path for the ow of oil to be cooled will beformed from cooler inlet ports 44 in the bottom of the shell Ill to acooler outlet port 4I in the top o! the shell i0 which communicates withthe outlet chamber of the fitting 21. Each of the sections I3 of thecooler contains a. bundle 4B of cooler tubes 41 which extendlongitudinally or from end to end of the shell and have at the endsthereof cooperating hexagonal enlargements 4l which are nested togetherso as to have the appearance of a honey comb, and which are securedtogether and to adjacent wall members of the cooler so as to close theends of the sections I3, such securing of the hexagonal end portions 4loi' the tubes being ordinarily accomplished by soldering.

The diametral dimensions of the enlargements 4l on the ends of the tubes41 determine the spacing of the tubes, or, in other words, determine arelationship between the tubes which shall be referred to hereinafter asthe normal spacing of the tubes. This normal spacing of the tubes isdesigned so as to provide relatively small interstices between theexteriors of adjacent tubes, through which the oil undergoing coolingaction may tlow in a manner to accomplish an eillcient transfer of heatfrom the oil to the metal walls of the tubes 41. Each bundle of tubes 46is so dimensionally formed with relation to the lateral dimensions ofthe chamber I3 in which it is contained as to provide between the sidesof each bundle and the wall of the shell I0 a deilnite oil flow passage50, and each bundle 46, lying above a. baille plate I4, is so formedwith respect to the vertical dimension of the section I3 in which it iscontained that a definite flow passage 5I is provided between suchbundle and the upper face of the baiile plate I4 therebelow. The howpassages 5Il result from the placement of circular spacer strips 59within the ends of the shell I0. The flow passages 5i result from theplacement of lateral spacer strips Gil between the end portions of thebaille plates I4 and the row 6l of tubes 41 immediately thereabove. Thislower row or bank 6I of tubes in each section above the lowermostsection is spaced at a distance from the row of tubes 62 thereabove,greater than normal. this being accomplished by placing between the ends48 of the tubes in the first row 6I and the ends 48 of the tubes in thesecond row 62 lateral spacer strips 63. In this way lateral ilowpassages 64 are formed between the first and second rows of tubes 6I andE2.

In Figs. 1 to '7 inclusive, the diameters of the tubes 41 and thehexagonal heads thereof are exaggerated with reference to the diameterof the cooler shell in order to simplify the drawings. In Figs. B and 9respectively I have shown the result in a cooler core in which the tubedimensions are shown in substantially accurate conformity toconventional proportioning between tubes and shell of known coolers.Reference is of course made hei io the relationship between the normalspacing between tubes on the one hand and tube diameter and shelldiameter on the other hand. It will be noted that the spacer rings 59provide, in conjunction `with the tubes and half-tubes, a peripheral orheader flow space which is well defined. which is not obstructed at anypoint, which receives heat throughout its length from the warm upcharnber I2, and which, as a result of the foregoing characteristics,provides a relatively low resistance flow passage for the distributionof warmed oil to the low resistance flow passages 5I penetrating thecore and also (through the apertures 1I) to the intertube spacesimmediately adjacent the core periphery, as described hereinabove. Atthe same time, because of the unobstructed characteristics of the llowpassage and its connection to the low resistance flow passages 5I,penetrating the cooler, excessive bypassing through the flow passage 50is inhibited and suflicient resistance is developed therein to promotethe penetration of the warmed oil to the core through the low resistanceilow passages 5I and the apertures 1i.

In Figs. 6 and 7 I have shown the characteristics of the pinchedhalf-tube 65 which is employed around the periphery of the core of thecooler in spaces where a regular, full sized, tube will not nt. Thishalf-tube $5 has a cross section corresponding to half of a hexagon ofthe size of the normal tube ends or enlargements 48. It has three walls66, 61, and 6B of the same width, the walls 6B and 68 being disposed atangles a of relative to the wall G1. A wall 69 connects the remainingedges of the walls 66 and 68 and is substantially twice the width of thewall 61. When two of the tubes 65 are placed together with the walls 69thereof in abutment, the walls G6, 61, and 58 of the two tubes will denea hexagon, and the walls 69 of these tubes will define a diametral planeextending between two opposite ridges or points of the hexagon. Each ofthe tubes 65 has near its ends pinched sections 10 wherein the walls BBand 68 are moved toward each other and are brought into substantiallyparallel relation.

and perpendicular to the wail 69, thereby forming in the opposite edgesof the tubes 65 depressions or shallow notches which, when the tubemember 65 is assembled in a cooler core, will provide apertures 1I forthe flow of oil from the peripheral iiow passage 50 into the interior oithe core. Accordingly, the provision of these depressions 1I in thehalf-tubes 65 contribute in the cooler construction to the effect 0fobtaining a rapid recovery of the cooler, from a congealed or partiallycongealed condition.

The formation of the pinched sections is accompiished by depressing aportion 12 of the wall 69, forcing a portion 'I3 of the wall B1 oppositethe wall portion 12 inward, and then squeezing the walls 86 and 68toward each other so that the moved walls in the pinched sections denesubstantially a letter N, as shown in Fig. 7,

Since the passages 50 and 5I are each dcned on one side by a wall whichis not cooled by air flowing thereover, there can under practically noconditions be any waxing of the oil in contact with the uncooled wall,and there will be consequently no restriction of the passages on theuncooled side thereof under congealment conditions. This characteristiccontributes to the free flow nature of the passages, and the inventionprovides for the maintenance of substantially unrestricted continuity ofthe passages through the cooler so as to provide a continuous flowchannel oi lower resistance under congeniment conditions than theresistance of the passages between the tubes.

I'he flow through this branching system of free flow passages may thusbe visualized by considering Figs. 1 and 2 simultaneously. From the coreinlet 44, the oil will ow in a direction generally parallel to thelongitudinal axis of the core, as indicated by the arrows 14. At thesame time, the oil will spread circumferentially in the peripheral freeflow passage 50 from the inlet 44 equally on either side of the bundleof tubes in the lowermost flow chamber I3. This combined axial andcircumferential movement (along roughly helical ilow paths) will bringthe oil to the ports I6 at the two side extremities of the bailles I4dividing the lowermost flow chamber I3 from the succeeding flow chamberI3. Then the free flow in the passages 50 will move in a generally axialdirection, opposite to that which occurs in the lowermost chamber I3,with suflcient circumferential movement to bring the "free flow" streamup to the next baille i4 in the side port (communicating with the shellwall) therein. The flow will alternate in this manner back and forthfrom end to end of the cooler on either side thereof until the twostreams reach the uppermost flow chamber I3 in which they will convergeby helical flow along the shell wall to the outlet 45.

The ow just described is the ow which occurs in what is herein referredto as the free flow" channel from the inlet to the outlet. From thisperipheral channel of ilow, the warmed oil will be urged to penetratethe core in the core penetrating free ilow passages 5| and 64respectively adjacent the baffles and between the rows oi tubes. Thesebranching flows of oil will also move in a direction generally parallelto the longitudinal axis of the cooler, and from such branching flows,the oil will gradually penetrate the more restricted passages betweenthe tubes so as to thaw out the congealed body of oil in the core.

Indicative of a practice now being followed with oil coolers, I haveshown a valve fitting or device 52 connected to the fitting 21 so as tocommunicate with the ports 31 and 38. This valve device 52 has a bypassvalve 53 to restrain flow of oil through the bypass chamber 34 duringnormal operation of the cooler. During such normal operation of thecooler, the hot oil flows through the inlet port 36 into the inletchamber 33, as indicated by the arrow 54 in Fig. 1. This oil then owslaterally through the port 42 in the side wall 3l of the fitting 21. asindicated by the arrows 55 in Figs. 1 and 3, into one end of the warm upchamber I2. The oil then ilows downward through the warm up chamber tothe bottom of the cooler and enters the lowermost chamber I3 of thecooler core through the ports 44 in the bottom wall of the shell IIJ, asindicated by arrows 5B. As indicated by full-line arrows 51, the oil owsserially through the consecutive flow charnbers I3 to the outlet port 45and thence on out through the valve device 52.

When oil becomes thickened or congealed in the cw chambers I3 oi thecooler core, the bypass valve 53 may open under pressure of the oilwhich has built up in the warm un chamber l2, and there will then be aflow of oil through the full length of the warm up chamber I2 from theinlet chamber 33 of the fitting 21 to and through the bypass chamber 34.This partial or complete freezing up" of the cooler core may result fromthe oil in the entire oil circulating system becoming cold-aa forexample, when the engine has been shut down for a period of time, or asudden drop in the temperature of the air passing through the tubes 41may cause a partial or complete congealmcnt of oil within the coolercore. When the bypass opens, the flow of heated' oil through the warm upchamber I2 heats the shell I which then conducts heat to the oil in theclearly defined flow passages I! lying adjacent the inner face of theshell. The ow will then spread through the branching system of free flowpassages in the manner described above. The

result of the free flow in the low resistance channels along theperiphery of the core from the inlet to the outlet, and the branchingflow from these channels penetrating the core, is to thaw out the entireinterior of the cooler within a remarkably short period of time ascompared to the time required to thaw out prior coolers of comparableeil'iciency.

While the warm up chamber has been disclosed as completely encirclingthe core, it is`to be understood that the branching system of free flowpassages can be employed in a cooler wherein the warm up chamber coversonly a portion of the area of the shell.

I claim as my invention:

l. A cooler for liquids which are viscous when cold, comprising: atubular shell, a warm up jacket surrounding said shell to impart heat tothe outer surface of said shell, a plurality of baille plates dividingthe space within the shell into a series of oil ilow path sectionsextending from side to side of the shell, liquid inlet means for thefirst section of said series, liquid outlet means for the last sectionof said series, alternate baille plates being provided with ports atopposite ends of said sections with at least one of said ports in eachbaille plate having its periphery partially defined by said shell toprovide a zigzag path of flow serially through all oi said sections inuninterrupted contact with the inner surface of said shell, a bundle oi'parallel open ended tubes within each of said sections and arranged inrows generally parallel to said baille plates, the majority of the tubesof each bundle being relatively closely spaced for efficient heatexchange between liquid flowing between said tubes and cooling fluidpassing through said tubes, means for spacing each end tube of each rowfrom said shell to provide a free flow passage for viscous liquidadjacent the inner surface oi said shell, means ior spacing at least onerow of tubes adjacent each baille plate from the adjacent baille plateto provide a free flow passage adjacent each baille plate communicatingwith the aforementioned free flow passage adjacent the inner surface ofsaid shell.

2. A cooler for liquids that are vis-cous when cold, comprising: ashell; means cooperating with the outer surface of said shell to definea warm up chamber from which heat may be imparted to the shell; baillemeans dividingr the space within said shell into a series oi flowchambers each having at least one extremity in contact with the innersurface of said shell in an area covered by said warm un chamber: liquidinlet and outlet means communicating with said chambers, said baillemeans and shell cooperatine to define port means through which theliquid may i'low from one of said flow chambers to another inuninterrupted contact with the inner surface of the shell: a bundle ofparallel open ended tubes within each oi' said chambers, arranged inrows generally parallel to said baille plate, the majority of said tubesof each bundle being relatively closely spaced for eillcient heatexchange between liquid flowing between said tubes and cooling iiuidpassing through said tubes; means for spacing each baille plate from anadjacent row of tubes a suflicient distance to provide a passage of lessresistance to flow of the liquid under congealment conditions in whichthe liquid tends to congeal upon the tube surfaces, than the resistanceo! the passages between the tubes; and means for spacing tubes adjacentsaid shell a distance from said shell sufiicient to provide passagesadiacent the inner surface oi the shell, of less resistance than thepassages between the tubes, connecting the inlet means and outlet meansrespectively to said passages adjacent the baille plates.

3. A cooler for liquids that are viscose when cold, comprising: a shell;means cooperating with the outer surface of said shell to denne a warmup chamber from which heat may be imparted to the shell; baille meansdividing the space within the shell into a series of flow chambers, eachhaving at least one extremity in contact with a heated area of the innersurface oi' the shell; liquid inlet and outlet means connected torespective chambers, said baille means being provided with port meansconnecting said chambers in series between said inlet and outlet meansto define a tortuous flow path through the cooler; a core comprising abundle of parallel open ended tubes Within each of said chambers,arranged in rows generally parallel to said baie means, the majority ofsaid tubes of each bundle being relatively closely spaced to providerelatively restricted passages for efficient heat exchange betweenliquid iiowing in said passages and coolant passing through said tubes;means defining between each baiiie plate and an adjacent row of tubes, acontinuous core penetrating free flow passage of less resistance thansaid restricted passages under congealment conditions in which theliquid tends to congeal upon the tubes; and means defining between theaforesaid heated areas of said shell and the adjacent tubes,` peripheralfree iiow passages of less resistance to flow than said restrictedpassages connecting the said core penetrating free iiow passages to saidinlet and outlet means respectively.

4. A cooler for liquids that are viscous when cold. comprising: a shell;means cooperating with the outer surface of said shell to define a warmup chamber from which heat may be lmparted to the shell; baille meansdividing the space Within the shell into a series of flow chambers, eachhaving at least one extremity in contact with a heated area of the innersurface of the shell; liquid inlet means and outlet means connected torespective chambers, said baille means being provided with port meansconnecting said chambers in series with said inlet and outlet means todeiine a tortuous flow path; a core comprising a bundle oi parallel openended tubes within each of said chambers, arranged in rows generallyparallel to said baille plates, the majority of said tubes of eachbundle being relatively closely spaced to dene relatively restrictedpassages for efficient heat exchange between liquid i'lowing betweensaid tubes and coolant passing through said tubes; means deliningbetween said heated areas of 'the shell and the tubes adjacent saidareas, a series of free flow passages which are connected to said inletand outlet means and through said port means to provide a substantiallycontinuous peripheral iree iiow channel which is of less resistance tothe flow of the liquid under congealment conditions in which the liquidadheres to the tubes, than the resistance of said restricted passages;and means defining between said baille means and an adjacent row oftubes a free ilow passage of less resistance to the iiow of said liquidunder said congealment conditions than the resistance of said restrictedpassages, said last mentioned free flow passage being in communicationwith said peripheral free iiow passage and penetratl0 ing the core toconvey into the core warmed liquid for facilitating the thawing o! thecore when it is ccngealed.

5. A cooler for liquids that are viscous when cold, comprising: a shell;means cooperating with the outer surface of said shell to define a warmup chamber from which heat may be imparted to the shell; baille meansdividing the space within the shell into a series of flow charnbers,each having at least one extremity in communication with the innersurface of the shell: liquid inlet and outlet means connected torespective chambers, said baille means being provided with port meansconnecting said chambers in series to provide a continuous tortuous iiowpath between said inlet and outlet means; a core comprising a bundle ofparallel open ended tubes within each of said chambers arranged in rowsgenerally parallel to said baille plates, the majority of the tubes oleach bundle being relatively closely spaced to provide relativelyrestricted passages for eflicient heat exchange between liquid fiowingin said passages and coolant passing through said tubes; means providingin each of said chambers a. core penetrating free flow passage betweenadjacent rows of tubes of greater spacing and less iiow resistance thanthe aforesaid relatively close spacing of the majority of the tubes tofacilitate penetration of the liquid into said bundles when the liquidis viscous; and means for spacing tubes from the inner surface of theshell to provide peripheral free iiow passages adjacent said areas, ofless resistance to iiow of the liquid under congealrnent conditions inwhich the liquid adheres to the tubes, than the resistance of the spacesbetween said majority of tubes, said peripheral free Iiow passagesconnecting said inlet and outlet means with said core penetrating freenow passages.

6. A cooler for liquids that are viscous when cold comprising: a shell;means cooperating with the outer surface of said shell to deiine a warmup chamber from which heat may be imparted to the shell; baille meansdividing the space within the shell into a series of liquid iiowchambers. each having at least one extremity in contact with a heatedarea of the inner surface of the shell; liquid inlet and outlet meansconnected to respective chambers, said baille means being provided withport means connecting said chambers in series between said inlet andoutlet means; a core comprising a. bundle of parallel open ended tubeswithin each of said chambers, arranged in rows generally parallel tosaid baille means, the majority of said tubes of each bundle beingrelatively closely spaced to provide relatively restricted passages forthe eiiicient heat exchange between liquid iiowing in said passages andcoolant passing through said tubes; spacing strips interposed betweensaid baille means and the ends of an adjacent row of tubes to providecore penetrating free iiow passages of less resistance than saidrestricted passages, to the iiow of liquid under congealment conditionsin which the liquid adheres to the tubes; and spacer rings interposedbetween the ends of said tubes and the shell to define peripheral freeiiow passages between said heated areas oi' the inner surface of saidshell and adjacent tubes, said peripheral free iiow passages connectingsaid inlet and outlet means respectively to said core penetrating freeiiow passages to provide a branching system of free iiow passages forconveying warmed liquid into the core, and said peripheral free flowpassages being serially connected by said port means to provide in saidsystem a substantially continuous free flow channel extending from saidinlet to said outlet means.

7. A cooler for liquids that are viscous when cold, comprising; a shell;means cooperating with the outer surface of said shell to define a warmup chamber from which heat may be imparted to the shell; baie meansdividing the space within the shell into a series of liquid nowchambers, each having at least one extremity in contact with a heatedarea of the inner surface of the shell; liquid inlet and outlet meansconnected to respective chambers, said baille means and shellcooperating to define port means serially connecting said chambers; abundle of parallel open ended tubes in each of said chambers arranged inrows generally parallel to said baille means. the majority of said tubesof each bundle being spaced relatively closely to provide restrictedpassages for the eflicient heat exchange between liquid flowing in saidpassages and coolant passing through said tubes; and spacing meansproviding, between said baille means and at least one row of tubesadjacent thereto, and between said heated areas of the shell and tubesadjacent thereto, a branching system of peripheral and core penetratingfree flow passages of less resistance to the low of liquid that hasbecome so cold and viscous as to adhere to the tubes, than theresistances of said restricted passages under said conditions, saidperipheral free ow passages being serially connected by said port meansto provide a substantially continuous free flow channel extending fromsaid inlet means to said outlet means in substantially uninterruptedcontact with said heated areas of the shell.

8. A cooler for liquids that are viscous when cold, comprising: a shell;means cooperating with the outer surface of said shell to denne a warmup chamber from which heat may be lmparted to the shell; baille meansdividing the space Within said shell into a series of flow charnberseach having at least one extremity in contact with the inner surface ofsaid shell in an area covered by said warm up chamber; liquid inlet andoutlet means communicating with said chambers, said baille means andshellcooperating to define port means through which the liquid may flowfrom one of said flow chambers to another in uninterrupted contact withthe inner surface of the shell; a bundle of parallel open ended tubeswithin each of said chambers, arranged in rows generally parallel tosaid baille plate, the majority of said tubes of each bundle beingrelatively closely spaced for eilicient heat exchange between liquidowing between said tubes and cooling fluid passing through said tubes;means for spacing each baille plate from an adjacent row of tubes asufficient distance to provide a passage of less resistance to flow ofthe liquid under congealsment conditions in which the liquid tends tocongeal upon the tube surfaces, than the resistance of the passagesbetween the tubes; means providing in each of said chambers a corepenetrating free flow passage between adjacent rows of tubes of greaterspacing and less resistance than the aforesaid relatively close spacingrof the majority of tubes to facilitate penetration of the liquid intosaid bundles when the liquid is viscous; and means for spacing tubesadjacent said shell a distance from said shell sumclent to providepassages adjacent the inner surface of the shell, of less resistancethan the majority of passages between the tubes, connecting the inletmeans and outlet means re- 12 spectively to said passages adjacent thebaille plates. and said free ilow passages.

9. A cooler for liquids that are viscous when cold, comprising: a shell;means dening a warm up chamber exteriorly of the shell; baiile meansdividing the interior of the shell into a tortuous flow passage one sideof which is in contact with the inner surface of the shell in an areacovered by said warm up chamber, said flow passage having an inlet andan outlet; a. bundle of openended tubes within each portion of the flowpassage disposed between the bailles, said tubes being in rows generallyparallel to said baiiles and the majority of said tubes of each bundlebeing relatively closely spaced; means for spacing the tubes adjacentsaid shell a distance from the inner surface of the heated area. of saidshell sufficient to provide a. continuous passage, adjacent said innersurface, of less resistance than the passages between said tubes; andmeans for spacing each baille plate from an adjacent row of tubes asuicient distance to provide a passage of less resistance to the flow ofliquid than the above mentioned spacing of the tubes, said passage beingconnected in the above mentioned passage of less resistance.

l0. The invention defined by claim 9 wherein there is means forproviding, in each of the portions of the flow path between the baflles,a core penetrating free now passage between adjacent rows of tubes ofgreater spacing and less flow resistance than the aforesaid relativelyclose spacing of the majority of tubes, said free flow passage havingone side in communication with said continuous passage.

11. A cooler for liquids that are viscous when cold, comprising: ashell; means cooperating with the outer surface of said shell to definea warm up chamber from which heat may be imparted to the shell; baillemeans dividing the space within the shell into a. series of flowchambers, each having at least one extremity in contact with a heatedarea of the inner surface of the shell; liquid inlet and outlet meansconnected to respective chambers, said baille means being provided withports connecting said chambers in series between said inlet and outletmeans to define a tortuous flow path through the cooler; a corecomprising a bundle of parallel open ended tubes within each of saidchambers, arranged in rows generally parallel to said baffle means, themajority of said tubes of each bundle being relatively closely spaced toprovide relatively restricted passages for efficient heat exchangebetween liquid ilowing 55 in said passages and coolant passing throughsaid tubes; means defining between each baille plate and an adjacent rowof tubes, a continuous core penetrating free ilow pasage of lessresistance than said restricted passages under congealment so conditionsin which the liquid tends to congeal upon the tubes; and means definingbetween the aforesaid heated areas of said shell and the adjacent tubes,peripheral free flow passages conmeeting the said core penetrating freeflow pas- 65 sages to said inlet and outlet means respectively, certainof said ports in said baille means being positioned in said peripheralfree flow passages to permit liquid flowing through said peripheral freeflow passages to pass from one flow chamber to another.

12. A cooler for liquids that are viscous when cold, comprising: ashell; means cooperating with the outer surface of said shell to denne awarm up chamber from which heat may be imparted to the shell; baillemeans dividing the space within the shell into a series of flowchambers, each having at least one extremity in contact with a heatedarea of the inner surface of the shell; liquid inlet and outlet meansconnected to respective chambers, said baille means being provided withports connecting said chambers in series between said inlet and outletmeans to define a tortuous flow path through the cooler; a corecomprising a bundle of parallel open ended tubes within each of saidchambers, arranged in rows generally parallel to said baille means, themajority of said tubes of each bundle being relatively closely spaced toprovide relatively restricted passages for etllcient heat exchangebetween the liquid ilowing in said passages and coolant passing throughsaid tubes; means dening between the aforesaid heated area of said shelland adjacent tubes, peripheral free-ilow passages, said peripheralfree-flow passages being connected to said liquid inlet and liquidoutlet means, arid the portions of said peripheral free-now passages insaid iiow chambers being connected to each other through said port meansthus forming a tortuous peripheral free-flow passage from said liquidinlet to said liquid outlet means; and continuous core penetratingfree-flow passage means extending laterally into said core from saidperipheral free-How passages whereby oil in said peripheral free-flowpassages may ow inwardly from the side of said core into the centralportion of said core.

13. A heat exchange unit of the class described comprising asupporting-shell, means dening a warm-up chamber, baille-means arrangedin said shell axially thereof with the opening in one baille-meanslocated at the opposite end from that in adjacent baille-means wherebythe interior oi said shell is formed into a tortuous fluid-flow passageextending axially of said shell with one side of said passage contiguousto said warm-up chamber, a bundle oi. open-ended tubes disposed in rowsparallel to said baille means and uniformly spaced apart betweenadjacent baite-means so as to establish a predetermined resistance toiiuid flow through said tortuous shell passage, and means spacing a rowof said tubes along one or more of said baille-means away from therespective baille-means a distance greater 4than the otherwise uniformspacing of said rows of tubes whereby the resistance to fluid flowadjacent said baule-means is less than that established by said uniformspacing of said tubes between adjacent bames.

14. A heat exchange unit of the class described comprising: asubstantially cylindrical shell: means defining a wann-up chamber on theexterior oi' said shell, inlet and outlet passages whereby hot fluid mayflow through said warm-up chamber: baffle-means within said shellextending axially ot said shell with the opening in one haine-meanslocated at the opposite end from that in adjacent baille-means. saidshell being thereby formed into a tortuous fluid-flow passage extendingaxially of said shell, with one side of said passage contiguous to saidwarm-up chamber; a bundle of open -ended tubes disposed in rows parallelto said baffle-means and axially of said shell, a. majority of saidtubes being uniiorrniJ spaced apart between adjacent baille-means so asto establish a predetermined resistance to fluid ilow through saidaxially tortuous shell passage;l and means spacing a row oi' said tubesalong one or more of said baille-means away from the respectivebaille-means a distance greater than the uniform spacing of said rows oftubes whereby the resistance to iiuid ilow adjacent said baille-means isless than that established by said uniform spacing of said tubes betweenadjacent baies 15. A heat exchange unit of the class describedcomprising a supporting-shell, means defining a warm-up chamber,baille-means arranged in said shell axially thereof with the opening inone baille-means located at the opposite end from that in adjacentbaille-means whereby the interior oi' said shell is formed into atortuous fluid-flow passage extending axially of said shell with oneside of said passage contiguous to said warm-up chamber, a bundle ofopen-ended tubes disposed in rows parallel to said baille-means andaxially oi' said shell, a majority of said tubes being uniformly spacedapart between adjacent bafflemeans so as to establish a predeterminedresistance to fluid flow through said tortuous shell passage, and meansspacing a row of said tubes along one or more oi' said baille-means awayfrom the respective baille-means a distance greater than the uniformspacing of the majori:y of said rows or tubes whereby the resistance tofluid flow adjacent said baffle-means is less than that established bysaid uniform spacing of said tubes between adjacent baffles. one edge ofthe larger space between the baille and the row ot tubes extending tosaid shell where said shell is warmed by said warm-up chamber.

SOREN K. ANDERSEN.

REFERENCES CITED The following references are of record in the ille ofthis patent:

UNITED STATES PATENTS Number Name Date 1,864,052 Dykeman et al. June 21,1932 1,923,404 White et al. Aug. 22, 1933 2,071,106 Blair Feb. i6, 103?2,270,864 Blais Jan. 27, 1942 2,307,300 Ramsau:- Jan. 5, i943 2,354,362Burns July 25, 1944 2,359,448 Shaw Oct. 3, 1944 2,359,538 Shogran Oct.3, 1944 2,373,157 Worth Apr. 10, 1945 No new references cited in reissueapplication.

Certificate of Correction Reissue No. 23,144 iSeptember 6, 1949 SOREN K.ANDERSEN 1L is hereby certified that error zippears in the printedspecification 0f the above numbered patient requiring correction nsfollows:

Column 9, line (i, for the word viscose read viscous; and that the saidLetters Patient should be read with this correction therein that thesame may conform to the record 0f the case in the Patent Ofiice.

Signed and sealed this 10th day of January, A. D. 1950.

[IML] THOMAS F. MURPHY,

Assistant Uommissoner o f Patents.

